Valve for rock drills



Oct. 7, 1930. w. A. SMITH. JR

VALVE FOR ROCK DRILLS Filed Nov/27, 1929 INVENTOR.

5 mil/k I11;

QZVL;

Hid/1 TTORNEK Patented Oct. 7, 930

UNITED STATES PATENT .OFFICE' WILLIAM A. SMIT H, JR, 0F IPHILLIPSBURG,NEW JERSEY, ASSIGNOR TO INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEWJERSEY, A CORPORATION OF NEW JERSEY VALVE FOR ROCK DRILLS Applicationfiled November 27, 1929. Serial No. 410,139.

This invention relates to rock drills, but more particularly to adistributing valve for fluid actuated rock drills of the hammer type.

The objects of the invention are to assure a rapid and positive actionof the'valve, to reduce the pressure fluid consumption of the drill towhich the valve may be applied to a minimum, and to assure a powerfulblow of the piston against the working implement.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawings illustrating the invention and in which similarreference characters refer to similar parts,

Figure 1 is a sectional elevation of so much of a rock drill as willserve to illustrate the invention and showing the valve in position toadmit pressure fluid into the rear end of the cylinder for actuating thepiston forwardly, and

Figure 2 is a similar view showing the valve in its other limitingposition.

Referrng more particularly to the drawings, A designates a cylinder of arock drill having a piston chamber B which is provided with a freeexhaust port or ports C. Within the piston chamber B is a hammer pistonD which controls the exhaust ports C and is adapted to deliver blows ofimpact to a working implement, only the shank E ofwhich is shownextending into the frontend of the piston chamber B. p

In the rearward'end of the cylinder A is an enlarged bore F to receiveavalve chest designated generally by G and comprising a pair of plates Hand J .which are suitably bored to form a valve chamber K. The plate Hin this instance is disposed adjacent the rear end of the piston chamberB to form a closuretherefor, and on the plate J is seated aback head Lwhich acts as a closure for y the rearward end of the cylinder A.

The back head L also serves as a casing for a throttle valve 0 having achamber P which may be in constant communication with a source ofpressure fluid supply through a suitable conduit (not shown). In thewall of the throttle valve'O is a port Q, to register with a passage Rin the back head and which passage R leads to a supply reservoir S inthe front end of the back head.

In accordance with the present invention the valve chamber K is formedin the plates H and J and in the back head L. The valve chamber Kcomprises an enlarged portion T which is located in the plate J and atthe forward end of the enlarged portion is an annular groove U whichopens with its rear Ward end into the enlarged portion T and is formedin the plate H.

In the plate J and rearwardly of the enlarged portionfl. wherewith it isarranged coaxially is a reduced bore V forming a part of the valvechamber K, and rearwardly of chamber B with the annular groove U for.

conveying pressure fluid to the rear end of the piston chamber toactuate the piston D forwardly. I

The'pressure fluid utilized for returning the piston D is conveyed tothe front end of the piston clfamber B by an inlet passage Y which leadsfrom the front end of the piston chamber to the bore V of the valvechamber,

and a supply passage Z in the plate J aflords constant communicationbetween the supply reservoir S and the enlarged portion T of the valvechamber K.

Disposed within the valve chamber K-is a distributing valve 6 having afiange'c which lies within the enlarged portion T of the valve chamberbut is of somewhatsmaller diameter.

than said portion T to enable the""pressure the rear inlet passages X.The flange c-has' a rearwardly extending stem d which extends slidablyinto the recess W for guiding the valve. i

Thevalve b is further provided with means at its front end to assist inguiding the valve '90 fluid to flow around the edge of the flangetoduring its IBClPIOCMJlOIlSZ'lIl the valve chamher. To this end anannular flange e is formed at the front end of the flange c to slidablyengagethe periphery; of a boss 7 in the plate H and which boss forms theinner b undingsurface of the annula r groove U.

The rearward end of the flange b constitutes a pressure surface 9,against an outer annular portion of whichpressure fluid constantly actstending to-throw the valve forwardly. 'An inner annulari portion h ofthe pressure surface g is intermittently exposed to pressure fluid toassist in holding the valve'in its feremost limiting position. Thisinner annular portion h is determined by a ring 7' on the plateJ whichforms an abutment for the flange 0 to limit the rearward travel of thevalve 6.

1 In order to assist the pressure fluid act- J ing against the pressuresurface 9 to actuate the valve 6 forwardly the stem (1 of the valve isprovided at its rear end with art actuating surface In which is adaptedto be intermittently exposed to pressure fluid. Such pressure fluid isconveyed into the rear end of the recess by a kicker passage 0 whichopens with its inlet end into the piston chamber B at a'point rearwardlyof the exhaimt ports C and is controlled by the piston D f 7 7,

Within the forward end of the'ivalve b and formed by the annular flangee is a chamber p, the end wall of which chamber constitutes an actuatingsurface q of larger area than thee actuating surface is. This actuatingsurface 9 is intermittently exposed to pressure fluid for throwing thevalve rearwardly. The pressure fluid utilized for this purpose isconveyed to the chamber p by a trip passage 1' which ieads from therearward end of the piston chamberB to the supply reservoir S and has abranch 3 which aflords constant communication oetweefi the trip passage1* and the chamber p. Preferably the communication between the trippassage .r and the'supply pas sage S is efl'ected'through a restrictedpassage t in the plate J On the forward end of the annular flange e is apressure surface it which is adapted to be intermittently exposed tocompression from the rear end of the piston chamber B to assist inthrowing the valve 6 rearwardly.

Means are provided to assure an early out off of the pressure fluid tothe ends of the piston chamber. that is. to effect a cut off of thepressure fluid at the instant the piston D starts to uncover the exhaustports C. To this end the valve 71 is provided with a shoulder 1: whichis adapted to extend slidably into the bore .V to cut off the flow ofpressure fluid from the enlarged portion T to the inlet passage Yshortly before the flange e ph e of the valve seats against the ringSimilarly, on the annular flange e is a shoulder a; which cooperateswith the outer peripher of the annular groove U to cut ofi the a missionof pressure fluid into said annular roove shortly before the valve 12reaches its oremost limiting position.

To the end that the piston D may deliver a powerful blow against theworking implement unhampered by compression in the front end of thepiston chamber B the stem d of the valve is provided with a port orports :0 which are in constant communicationwith the bore V andtherefore with the inlet passage Y. The ports a: are adapted to registerwith ports 7 in a plug 2 which extends through the valve 5 and is seatedwith its rear end inthe back head L and with its forward end in theplate H. The plug a is provided with a passage 2 wherewith the ports 1communicate and said passage opens with its rearward end into an exhaustpassage 3 in the back head L and leading to the atmosphere.

In order to provide an outlet for the pressure fluid admitted to theactuating surface is after the valve 1) has been moved forwardly theplug a is provided with the port or ports 4 which are controlled by therear end of the stem (Z of the valve; The ports 4 are located rearwardlyof the port y and also open into the passage 2 in the plug a.

The operation of the device is as follows: With the valve in itsrearmost position as illustrated in Figure 1, pressure fluid wiil flowfrom the enlarged portion T of the valve ehamber around the edge of theflange a into and through the annular groove U and the inlet passages Xinto the rear end of the piston chamber to drive the piston D forwardly.I

It will be observed that while the piston D is in the rearmost positionit will cover the trip passage 1' or that pressure fluid flowingthereinto will enter the chamber 1) through the branch 8 and will actagainst the actuating surface q to maintain the valve in the positionstate-d.

As the piston D proceeds forwardly and shortly prior to the uncoveringof the exhaust ports C thereby, the said piston will uncover the kickerpassage 0 to admit 'pressure fluid into the rearward end of the recess Wto act against the actuating surface is. The pressure fluid thusadmitted to the actuating surface is together with tha-tacting againstthe pressure surface 9 combine with the force of the suction created bythe pressure fluid on the edge of the flange c to throw the valve 6forwardly at the instant the piston D starts to uncover the exhaust portC, thus preventing an escape of pressure fluid directly from the sourceof supply through the piston chamber to the atmosere.

With'the drop in pressure in the'rearward end of the piston chamber thepressure within the chamber will of course also be reduced so that t eopposing pressures may the rear end of the stem d will uncover the ports4 so that the pressure fluid acting against the actuating surface is mayescape through the said ports 4 into the passage 2 and thence throughthe passage 3 to the atmosphere.

After the valve has been shifted to the new position described, pressurefluid will flow over the pressure surface p into the bore V and thencethrough the in et passage Y to the front end of the piston chamber toactuate the piston rearwardl When the piston reaches a position to orm aclosure for the trip passage 1' pressure fluid leaking thereinto willflow into the chamber 10 and will act against the actuating surface qtending to throw the valve rearwardly.

As the piston proceeds rearwardly it will uncover the exhaust port C sothat the pressure fluid may exhaust from the front end of the pistonchamber to the atmosphere and in consequencethere will be a drop inressure rearwardly of the flange a. At t e same time the air in the rearend of the piston chamber B will be compressed by the piston and willact against the pressure surface'u.

Such compression, together with the pressure fluid acting against theactuating surface 9, will then return the valve 1) to its initialposition,

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and apiston therein, an exhaust port for the cylinder controlled by thepiston, a valve chest having a valve chamber, inlet passages leadingfrom the valve chamber to the cylinder, a distributing valve in thevalve chamber comprising a flange over which pressure fluid flows to oneinlet passage, a pressure surface on the flange c0n stantly exposed topressure fluid tending to throw the valve in one direction, an actuatingsurface on the valve intermittently exposed to ressure fluid to assistthe pressure fluid actmg against the pressure surface in throwing thevalve, an opposed actuating surface on the valve intermittently exposedto pressure fluid for throwing the valve in the opposite direction,passagescontrolled by the piston for delivering pressure fluid to theactuating surfaces, and means on the valve to effect an early cut off ofpressure fluid to the cylinder.

2. In a fluid actuated rock drill, the combination of a cylinder and apiston therein, an

exhaust port for the cylinder controlled by the piston, a valve chesthaving a valve chamber, inletpassages leading from the valve chamberto-the c linder, a distributing valve in the valve 0 amber comprising aflange over which pressure fluid flows to one inlet passage, a pressuresurface on the rear end ofthe flange constantly exposed to pressurefluid tending to throw the valve forward,

an actuating surface on the valve intermittently exposed to pressurefluid to assist in throwing the valve forward, an opposed actuatingsurface on the front end of the -valve intermittently exposed topressure fluid for throwing the valve rearward, passages controlled bythe piston for delivering pressure fluid to the actuating surfaces, andshoulders of the valve cooperating with the valve chamber to cut off theadmission of pressure fluid to the cylinder.

3. In a fluid actuated rock drill, the combi- 4 nation of a cylinder anda piston therein, an exhaust port for the cylinder controlled by thepiston, a valve chest having a valve chamber, rear and front inletpassages leading from the valve chamber to the cylinder, a distributingvalve in the valve chamber comprising a flange over which pressure fluidflows to the rear inlet passage, a pressure surface on the rear end ofthe flange constantly exposed to pressure fluid tending to throw thevalve forward, a rearwardly extending stem on the valve having anactuating surface against which pressure fluid intermittently acts toassist in throwing the valve forward, an actuating surface on the frontend of the valve against which pressure fluid intermittently acts forthrowing the valve rearward, passages controlled by the piston fordelivering pressure fluid to the actuating surfaces, shoulders on thevalve cooperating with the valve chamber to cut ofl' the admission ofpressure fluid to the cylinder at the instant of uncovering of theexhaust port by the piston, and ports and passages conof the valveintermittently exposed to pressure fluid to assist in throwing the valveforward, a kicker passage leading from the cylinder to the valve chamberto s deliver pressure fluid to'the actuating surface and controlled bythe piston, an actuating surface on the front end of the valve, a trippassage affording communication between the cylinder and a source ofpressure supply and having ,a branch for delivering pressure fluid tothe second said actuating surface, a pressure surface on the front endof the flange intermittently exposed to compression to assist inthrowing the valve rearward,

shoulders on the opposite ends, of the flange pressure fluid tending tothrow the valve for- -ward, an actuating surface on the rear endcooperating with the valve chamber to cut. off the flow of pressurefluid to the cylinder at the instant of uncovering of the exhaust portby the piston, and ports and passages controlled b the valve forrelievin compression from t e front end of the cy inder.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR.

